Craniosynostosis, the premature fusion of 1 or more cranial sutures is a common malformation occurring in 3 to 5 per 10,000 live births. Most often craniosynostosis occurs as an isolated (i.e. nonsyndromic) anomaly. Nonsyndromic craniosynostosis (NSC) is a heterogeneous condition of multifactorial etiology with evidence of genetic factors. Significant progress has been made in understanding the clinical and molecular aspects of monogenic syndromic craniosynostosis. However, the phenotype characterization of NSC and the variability within diagnostic subgroups is incomplete and the causes of NSC remain unknown. Analysis of the clinical features and the craniofacial anthropometric profiles of a large group of prospectively recruited patients with sagittal and coronal NSC evaluated under a standardized protocol will further characterize these phenotypes. The clinically homogeneous group of patients with isolated nonsyndromic sagittal craniosynostosis will be used to identify causative genes by candidate gene association analysis. We have already enrolled and characterized 100 sagittal and 39 coronal NSC families and our existing recruitment system will ensure at least 250 additional sagittal and coronal NSC families by year 4 of this study. We will use advanced imaging technologies and quantitative morphological tools to characterize and evaluate 3D phenotypic variation within and between the diagnostic categories of sagittal and coronal NSC. The genotyping of the first 47 case-parent trios with isolated sagittal NSC was initiated and the results indicate associations with a region on chromosome 3q and with several of the tested candidate genes. Our efforts will be dedicated to reproducing and validating these associations and to identifying variants within these genes that predispose to NSC. We will also continue SNP-based genotyping and the association analysis of additional candidate genes. In summary, this application proposes a multicenter phenotype and genotype study aimed at determining the clinical, anthropometric, and molecular characteristics of NSC. Our aims are to accrue well-characterized sagittal and coronal patient populations, to identify areas for improved clinical care, and to establish a sample repository available to the scientific community. In addition, we will also identify genes associated with sagittal NSC. The resources that we have amassed and the collaborative and integrated approaches that we will utilize put us in a unique position to accomplish these aims.